I mostly get my products from NewEgg and CDW. My current CDW rep is pretty good. The best thing about my rep is he admits software licensing is crazy and talks with his team to find me the right licenses every time.
YMMV but I give a +1 lately to CDW. I have been to a couple local events and they admit they will not be the lowest price but are trying to offer better services and side benefits.
After reading many SW/blog posts by SAM, I do watch out for the VAR related issues.
Edit: - As for finding the right MS software licenses on CDW, don't waste your time. If you don't find the correct MS Part-# just ask your rep to find out. As you found out CDW will list every single license from all types of MS contracts (Government, Open Value, Open License, 0-5 users, 100+ users, 500+ users). It is not worth the pain. It is better if you ask your rep, "Can you find me a W2016 Standard License with 16 Cores?" or "Can you find me 20 2016 RDS User CAL's under my Open Value license?"